The Enlightenment

The characteristics of the Enlightenment are a scepticism
towards the doctrines of the church, individualism, a belief in
science and the experimental method, the use of reason, that
education could be a catalyst of social change and the demand for
political representation. Its main social and political
consequence was the French revolution.

The core period of the Enlightenment was second half of the eighteenth century.
The thinkers associated with the Enlightenment include d'Holbach (1723-89) and
the Encyclopedists in France, David Hume (1711-76) in Scotland and Kant
in Germany. To understand the Enlightenment we have to look at what preceded
it.

The battle of ideas that was to culminate in the Enlightenment began in the
seventeenth century. Francis Bacon (1561-1626) advocated the use of scientific
method and René Descartes (1596-1650) proposed a critical rationalism.
The Enlightenment can be understood as the culmination of the move away from
the authority and dogmatism of the mediaeval and the awakening of modernity.

Medieval philosophy combined Christian beliefs with the ideas
of Plato and Aristotle. In the medieval world philosophers
respected their predecessors and accepted their methods. If a new
discovery about nature contradicted one of Aristotle's
principles, for example, it would probably have been assumed that
it was the discovery that was in error.

Enlightenment thinkers were not content to accept appeals to
Aristotle's authority. It could be seen that using experimental
methods science was progressing and increasing our understanding
of nature, which could not have been done without rejecting some
of Aristotle's assumptions.

It was not only Aristotle that was being questioned, using
reason and logic philosophers criticised political and religious
ideas. What rational answer is there for the justification of
monarchy or that you should choose one type of religion over
another?

Rationalism

A Rationalist is a philosopher who believes that we can gain
knowledge by the use of reason alone, without reference to the
external world.

Rationalism has a long history in philosophy, Plato (c.
427-347 BC) was a rationalist. René Descartes (1596-1650), the
"father of modern philosophy" was the first modern
rationalist. He felt that philosophy should move away from the
beliefs of the medieval scholastics and found itself on firm
foundations. He was looking for certainty, and used his method of
doubt to try and find what was indubitable.

He imagined that his whole life could be a hallucination
caused by a "malicious demon". If this was the case,
what could he be sure of? Descartes realised that he could not
doubt that he was thinking, as doubt is a type of thought. So,
without any reference to the external world Descartes was sure
that he had found a basic truth that could not be questioned. Of
course once he released that he was thinking he could no longer
doubt that he existed (something must be doing the thinking).
This enabled him to build up a philosophical system based on
thought alone.

Once Descartes had reintroduced, critical questioning into
philosophy the scene was set for the hundred-year struggle that
was to lead to the Enlightenment.

Other rationalist philosophers include Spinoza, Leibniz, Kant
and Hegel.

Empiricism

Empiricism is the belief that all knowledge comes from
experience. The "empirical world" is the world of the
senses, i.e. the world we can see, feel, touch, hear and smell.

John Locke (1632-1704) thought that the human mind at birth
was a tabula rasa (blank tablet) on which experience writes the
general principles and details of all knowledge. This is
completely opposite to the rationalists (see above). Whereas a
rationalist would attempt to find knowledge by thought alone, an
empiricist would use the methods of the experimental sciences.

This emphasis on science and experiment is one of the
characteristics of the Enlightenment. D'Holbach (1723-89)
published his Systèm de la nature (1770) in which he asserted
that explanations of nature should not be sought in traditional
beliefs or the "revelations" of the church, but through
the application of scientific method

It was not until Kant (See later) that empiricist and
rationalist strains were bought together.

The Encyclopedists

The Encyclopédie ou Dictionnaire Raisonné des Sciences, des
Arts et des Métiers was published in seventeen volumes between
1751 and 1765. Its aim was to provide information on every sphere
of knowledge, and in particular to promote the application of
science in industry, trade and the arts. It is seen by many as
epitomising the sprit of the Enlightenment.

Denis Diderot (1713-1784) was the main editor. He was a committed empiricist
and wrote on philosophy, religion, political theory and literature. He was highly
critical of the church's influence on ideas.

Voltaire (pen name of François-Marie Arouet) (1694-1778) also
edited and contributed to the Encyclopédie. He was
anti-Christian and critical of the clergy, the king and the
privileges of the nobility. He was highly influential in the rise
of liberal thought in continental Europe.

Jean-Jacques Rousseau (1712-1778) wrote on music and political
economy. Later he quarrelled with Diderot and came to regard the
Encyclopédie as the work of the devil.

Rousseau was not alone. In 1752 and 1759 the Jesuits managed
to suppress publication, although in each case for only a short
period. Diderot however remained firm and by 1772 a further
eleven volumes of plates were published. Diderot's ambition
"to change accepted habits of thought" was in largely
successful.

The analytic/synthetic distinction

Some statements we judge to be true or false in relation to
facts in the world, for example that you are now in reading this
book. That you are reading this book is called by philosophers a
synthetic truth.

Other statements we judge to be true due to the meanings of
the words involved. We can know that the sentence "All
bachelors are unmarried." is true without having to do a
survey of bachelors, because the sentence is true by definition.
It is an analytic truth.

Synthetic truths are "truths of fact" and analytic
truths are "truths of reason". We use empirical methods
to verify synthetic statements and rationalist methods to verify
analytic statements.

Kant was the first to use the terms Synthetic and Analytic. He
pointed out that all analytic truths are necessary, that is, they
could not have been otherwise. If you agree that the definition
of a bachelor is an unmarried man, then it stands to reason that
all bachelors are unmarried.

Synthetic statements are not necessary. Philosophers use the
word contingent to describe something that is not necessary. It
is not necessarily true that you are reading this webpage: you could
be reading a printout, for example.

It is important to make the analytic/synthetic distinction in
argument. If you try to argue that something is true you need to
be clear about whether you are saying something about the
empirical world, or whether you are clarifying the meanings of
words. It would do you no good for example to hunt for a bachelor
who was married to try and refute the statement. It would be no
help to you to try and find a "good murder" to refute
the statement that all murder is bad, because murder is by
definition bad.

Logic

Good philosophy must be based on good arguments, not arguments
in the sense of quarrels, but reasoned arguments. Logic can be
understood as the science of proper reasoning; what separates a
good argument from a bad one. A useful way to understand
arguments and what makes them good or bad is to divide them into
two types: Deductive and inductive.

In a deductive argument, the conclusion is said to be true if
it follows from the premises (starting statements). The best
known form of a deductive argument is the syllogism, the simplest
of which consists of two premises and a conclusion:

Premise 1 All Philosophers are Wise

Premise 2 Socrates is a philosopher

Conclusion Therefore, Socrates is wise.

However if the first premise was "Some philosophers are
wise" we could not be sure that Socrates was wise, as he may
have been one of the philosophers who wasn't. Deductive logic
does not appeal to empirical evidence, so long as the premises
are true and the argument is valid then the conclusion must be
true.

Inductive logic is concerned with making generalisations about
the empirical world based on observation. It is closely connected
with experimental science (an experiment is a particular type of
observation). Let's say we were interested in the personality of
people with different astrological signs and we observed that
Virgo's were tidy. We may want to make a generalisation based on
this. However, although our observations may back up this
generalisation we cannot be sure that it applies to all Virgo's,
only those we have observed. There may be Virgo's in the future,
or in some other country that are not like that.

Determinism

The idea of determinism is that all events are the results of
previous causes. If we heated a bar of iron, and the bar
expanded, we would say that the heat was the cause of expansion.

The idea of a physically determined universe is associated
with Sir Isaac Newton (1642-1727). This is sometimes called the
billiard ball view of nature: A billiard ball will only move when
acted on by another force such as another billiard ball hitting
it. If we could measure the exact velocity and angle of the first
billiard ball, we could predict the movement of the second.

The philosophical problem comes with human beings. If we were
to accept the empirical view that human beings are organised
systems of matter and that our minds are formed as a result of
experiences then we may want to explain human behaviour in terms
of cause and effect.

If we knew enough about the biological make up of an
individual, his early childhood experiences and the social and
historical circumstances he was born into, then perhaps we could
predict all of his actions. From this point of view the idea of
free will (the ability to choose) is simply the result of or
ignorance of all of the causal factors.

This is as much a problem for the present day as it was for
the thinkers of the Enlightenment. I may think that I am in love
with a unique soul mate, but it may be that my body is producing
chemicals that make me fall in love in order that I reproduce the
species.

If there is no such thing as free will then we cannot apply
moral concepts such as good and bad. Morality can only exist were
there is choice, i.e. that a person could have done otherwise.

Of course, if we believe that human nature is something other
than the result of previous causes, then we may argue that people
do have responsibility for their actions.

Kant

Immanuel Kant (1724-1804) is regarded as one of the most
important philosophers ever. A major figure of the Enlightenment
he tried combine both rational and empirical strands in his
philosophy.

He wrote on the natural sciences, metaphysics (what reality
is), morality and religion.

He was impressed with progress in the natural sciences
following Newton and was concerned that philosophy in contrast
was muddled and filled with disagreement. His project was to try
and find if philosophy could say anything at all.

He thought that the role of philosophy was to uncover how
human beings understand or categorise the world. One of his
conclusions is that we make sense of the world is through
categories such as space and time. We impose these categories on
objects, and they are a property of our understanding rather than
properties of objects.

In moral philosophy, he starts from the idea that all human beings are rational
and autonomous (free to make choices). From this starting point he went on to
say that universal moral laws are possible. (See
categorical imperative later).

Kant would have liked to have found a sound philosophical basis for belief
in God, however he found all philosophical attempts to prove Gods existence
unsatisfactory (See Philosophy and the proof of God's existence). For Kant
whether God exists is a question of faith rather than reason.

All western Philosophy since the Enlightenment has been
coloured by Kant, and philosophers today are still actively
engaged in debating his ideas.